Utility companies commonly use flow meter assemblies to measure a fluid flowing through a conduit to a residential or commercial end user. For example, when water flows through a flow tube housing of an electromagnetic flow meter assembly, it wets a porous material (e.g., graphite, porous plastic or gypsum) that surrounds an electrode in a cavity of the flow tube housing. The wetted surface of this porous material contacts an active surface of the electrode and the flow meter assembly uses magnetive induction to determine a rate of the water flow through the fluid passageway.
It is recognized herein that when a flow tube is filled with fluid, air bubbles or particles become trapped between the wetted surface of the porous material and the active surface of the electrode. This changes the surface area in which the wetted surface contacts the active surface of the electrode. Without a constant active/wetted surface area, the measurements of the flow meter assembly become inaccurate. This problem is exacerbated with changes in water pressure.